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  1. chileheadcraig

    Sizing distribution main for fire pumps

    We have a maximum velocity limit of 10 ft/s used as guidance for sizing water mains in our system, which includes fire flows. It seems that when this topic is discussed, its with regard to the design fire demand. My question/concern is with regard to if a building needs a fire pump. Per NFPA...
  2. chileheadcraig

    Extremely unusual distribution system pressure drop

    I work for a water utility and we have a conundrum that none of us can figure out. One of our zones is a pump station/water tank fed setup where water going to the distribution system is controlled by tank level. While a typical setup would consist of a pump station being tripped on and off by...
  3. chileheadcraig

    "local" Transients

    I work at a water utility and we have had some customer complaints about noisy pipes. We have done the standard checks, which include inspecting the meter and double checks at their service connection and making sure all line valves are fully open. We also advised them of the possibility of...
  4. chileheadcraig

    10 State Standads chem feed pump requirements

    I was looking at permitting some chemical feed pumps and they technically do not meet the following 10 State Standsrds: 4.7.2, Fluoridation – Chemical feed equipment and controls e. a fluoride solution shall be applied by a positive displacement pump having a stroke rate not less than 20...
  5. chileheadcraig

    headloss gravity flowing through pump and/or through ARV?

    We are evaluating a scenario where the check valves would be replaced with spool pieces and flow would be allowed to flow backwards through the high service pump in order to facilite drainage of a reservior in emergency situations. My question is how should I approximate the headloss due to...
  6. chileheadcraig

    NPSH and TDH

    There is a discussion between myself and another engineer as to the actual definition of TDH (total dynamic head), being the head condition that is specified to the pump manufacturer for the duty point. Assume that this is a suction lift pump (so that both suction and discharge lifts are +)...
  7. chileheadcraig

    best pump for final clarifier scum?

    What would you recommend that can operate without a flooded suction? The scum wetwell is up to 15' deep, so I am thinking that a submersible is the only solution.... any thoughts? Thanks.
  8. chileheadcraig

    ChemClean acid filter wash?

    A WWTP operator requested a ChemClean Filter Cleaning System that is essentially an acid wash that cleans the filter media during backwash. Does anyone know where I can find a rep for this type of system to get budget pricing and more info? Thanks in advance!
  9. chileheadcraig

    6"x2" reducer

    I'm working on a pipe replacement program and we have a lot of 6"x2" reductions (mainly after fire hydrants). ADIP does not list this as an available fitting... so is this a fitting that can be easily purchased by a contractor (possibly by another manufacturer) or should I just use a...
  10. chileheadcraig

    how to NOT undo pan and zoom

    When doing commands, I frequently zoom and pan to make sure the correction looks right and then when trying to undo, I have to undo all the panning and zooming before I can undo the last actual command. Is there a way do disable undo-ing pan and zoom? Thanks
  11. chileheadcraig

    low flow submersible

    I am looking for a submersible pump with an operating point at 105 gpm at 38 ft TDH. Most of the pumps I've seen in this range operate near the shutoff point. Any suggestions? Thanks in advance.
  12. chileheadcraig

    pressure loss in air piping

    We are desinging a blower system for an aeration basin and I need to size the blower header. I am familiar with calculating head loss in water piping, but have not done it for air. Our air requirements are 1400 SCFM per basin. I will need to accout for losses in straight steel piping with...
  13. chileheadcraig

    Centrifugal Screw Pump - any opinions?

    After posting a topic regarding PD type pumps, it appears to be more of a headache than its worth. We are now considering a centrifugal screw pump for the slugde pumping application (RAS/WAS). It does not appear to be very common, but looks as if this is the right pump for the job. How is the...
  14. chileheadcraig

    PD vs Centrifugal pumps

    Does anyone know where I can find design information for selection of PD pumps that will operate in parallel? Any pros and cons of using them for pumping municipal sludge (for a RAS/WAS station) vs a celtrifugal pump? I am only used to design of centrifugal pumps. Thanks.
  15. chileheadcraig

    'mix valve' design for lift station

    I am doing a upgrade for an exisiting lift station with a siltation problem. It has been suggested to use a 'mix valve' design that will re-suspend the sediment when pumping begins. Anyone have experience with this design? I've never heard of it.

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